Art Deco Marcasite Marquise Ring 800 Silver Vintage Size 6.5. This antique estate ring dates from the 1920s and is likely European in origin. The silver band is topped with a marquise shape set with marcasite stones in varied sizes. The piece is in excellent vintage condition, with a light patina you may polish yourself. Its inner band is stamped SILVER, and it tests as 800 silver.